Door operator



Dec. 2, 1969 F. A. PURDY 3,431,337

DOOR OPERATOR Filed Jan, 18, 1968 2 Sheets-Sheet 1 Dec. 2, 1969 FiledJan. 18 1968 F. A. PURDY DOOR OPERATOR 2 Sheets-Sheet 2 United StatesPatent 3,481,387 DOOR OPERATOR Frederick A. Purdy, 870 United NationsPlaza, New York, N.Y. 10017 Filed Jan. 18, 1968, Ser. No. 698,901 Int.Cl. Ef 15/20; E05d 15/38 U.S. Cl. 160-188 11 Claims ABSTRACT OF THEDISCLOSURE A motor operated door having a light sensitive cell foractuating the door motor for opening and closing the door and a safetyswitch in the motor control circuit, the safety switch being connectedby a spring and chain to a collar on the motor shaft so that, if thedoor is stopped by an obstruction during opening or closing, the springand chain will open the switch to stop the motor after the motor hasoperated through its normal cycle.

BACKGROUND OF THE INVENTION This invention relates to motor operateddoors and, more particularly, to a safety switch in the motor controlcircuit for such a door.

In my U.S. Patent No. 3,248,630 there is shown and described a motoroperated door wherein a motor, connected through a double-disc, springcompressed, grip sheave and cable to the door, is actuated by theheadlight beam of a vehicle to open and close the door. When the motor,in opening the door, brings the door to its fully opened position, themotor is reversed and, when next operated, closes the door. Conversely,when the door reaches its fully closed position, the motor is againreversed for subsequent door opening.

As has been noted, the motor is connected to the door through adouble-disc, spring compressed, grip sleeve and a cable. The cable isgripped between the spring compressed discs and, in normal operation,the motor, in turning the grip sheave, operates the cable connected tothe door. The spring on the grip sheave is adjusted so that, during suchnormal operation, the discs of the grip sheave grip and turn the cablebut, if the door encounters an obstruction, such as, a bicycle, tool, orthe like, the cable slips between the grip sheave discs. This, ofcourse, prevents damage to the door, the control mechanism and theobstructing object but, unless the motor is turned off, the motorcontinues to run.

SUMMARY OF THE INVENTION In the instant invention, a double-disc, springcompressed, grip sheave is afiixed to the end of a door operating motorshaft and the motor shaft is connected to a switch in the electric leadssupplying electrical power to the motor. The switch is connected to themotor shaft in such a way that, during normal operation of the motor inthe first direction to open the door and in the reverse direction toclose the door, the switch remains closed and power to the motor is notinterrupted by the switch. However, if the door encounters obstruction,or is otherwise held in position while the motor is running, therebycausing a cable to slip on the grip sheave, after the motor has turnedto grip sheave a prescribed distance beyond the grip sheaves normalcycle of operation to open, or close, the door, the switch is thenopened, thereby cutting olf the power to the motor and stopping themotor.

The switch, and the connection of the switch to the shaft in the instantinvention are relatively simple. Once the obstruction holding the doorhas been removed, the connection of the switch to the motor shaft can beeasily reset and the door operator will, thereafter, open 3,481,387Patented Dec. 2, 1969 and close the door in the normal cycle, withoutinterference from the switch, until such time as an obstructron toopening or closing of the door again occurs.

DESCRIPTION OF THE DRAWINGS The instant invention will be understoodfrom the following description and the appended drawings illustratingthe preferred embodiment of the invention and in which:

FIGURE 1 is an elevation-view, partially broken away, and partially indiagram, and viewed toward one jamb of a garage-doorway, showing abracket on the doorways inner facing and cable-pulleys on the bracket,portions of the vertical and horizontal tracks and the curve track, thedoor operator motor mounting, with switch, and the motor controlcircuitry, diagrammatically;

FIGURE 2 is a view, partly in section, taken along line 2--2 of FIGURE1;

FIGURE 3 is a view taken along line 3-3, FIG- URE 2;

FIGURE 4 is a view taken along line 4-4, FIG- URE 3;

FIGURE 5 is an elevation-view of the switch; and

FIGURE 6 is a top plan view of a portion of the mechanism of FIGURE 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Door 2 is of the conventionaloverhead type and is made up, in the usual manner, of horizontallyextending sections hinged together, only the top section being shown inFIGURE 1. Door 2 is guided in vertical track 4, curve track 6 andhorizontal track 8 by track engaged roller 10 connected by pin 12 andbracket 14 to door 2'. A counterbalancing spring 14 is connected bypulleys 16, 18 and cable 20 to door 2, in conventional manner, forcounterbalancing the weight of the door as the door is opened andclosed, in the customary manner employed with both manual and motoroperated doors.

As shown in FIGURE 1, door 2 is connected by pin 12, carried by bracket14, to links 22, 24, 26, 28, 30 and rollers 32, 34, 36, 38, 40, and byplate 44, held by cotter pin 43 on shaft 42 of roller 40, to endlesscable 46 which, at the forward end of horizontal track 8, passes aroundpulley 48 mounted on the door frame and, at the opposite end of thetrack, passes around grip-sheave, generally designated 50. For purposeof adjusting the tension of endless cable 46, turn-buckle 52 isattached, .at its opposite ends, to the ends of cable 46 to form thecable in an endless loop around pulley 48 and grip-sheave 50. The upperand lower runs of cable 46 have, adjustably affixed to the cable,shipper buttons 54, 56, respectively, for purposes later described.

As has been noted, when grip-sheave 50 is rotated in a first direction,door 2 is moved from the closed position to the open position and, Whengrip-sheave 50 is rotated in the opposite direction, door 2 is movedfrom the open position to the open position. This is accomplished byreversing the direction of the drive of grip-sheave 50 when door 2reaches its fully opened and fully closed position by a mechanicallinkage, such as shown and described in my U.S. Patent 3,248,630 whichmechanical linkage is tripped by shipper buttons 54, 56, in the mannerdescribed in my aforementioned patent, to control the operation of theelectrical control circuitry of the motor driving grip-sheave 50. Forpurposes of illustration and a better understanding 'of the instantinvention, the mechanical linkage for controlling the circuitry of thegrip-sheave drive motor and for reversing the drive direction ofgrip-sheave 50 is not shown or described, reference being had to theillustration and description thereof in my aforementioned patent.

Referring to FIGURES 1 and 2, grip-sheave 50 is made up of two taperedfaced pulley heads 62, 64 keyed to shaft 66 of grip-sheave drive motor68. Pulley half 64 is urged, by compression spring 70, on shaft 66,toward pulley half 62 to grip cable 46 between the tapered faces ofpulley halves 62, 64. The compression of spring 70, urging pulley half64 toward pulley half 62, is adjusted by nuts 72, 74 threaded onto theend of shaft 66. Motor 68 and grip-sheave 50 are supported in frame 76afiixed to horizontal track 8, or to the garage structure.

Switch, generally designated 80, having housing 82, is glued, welded orotherwise suitably attached to frame 76. Stationary contact 84 iscarried in housing 82 by a fixed, non-conductive, mounting 86, mountedin fixed position in housing 82. Contact 84 is connected, by lead 88, toone side of power source 90. Moveable contact 92, mounted innon-conductive mounting 94 slideable in housing 80, is connected by lead96 to motor 68, for purposes to be described. At the upper end of switch80 a nonconductive guide 98 is fixed to housing 80 by cotter key ablemount '94, urging contact 92 toward and into contact with fixed contact84.

Referring to FIGURES 2 and 5, rod 100, with moveable mount 94 andmoveable contact 92, is moveable in housing 80 and guide 98 in thedirection of the arrow in FIGURE but, for reasons more obvioushereinafter, is not rotatable in guide 98. The upper end of rod 100 isconnected by tightly coiled spring 110, press fitted through an opening112 through the end of rod 100, and chain 114 to collar 120 clamped onshaft 66 between collars 122, 124. For reasons later described, collar120 is not keyed to shaft 66 but, during normal operation of motor 68,turns with shaft 66. Chain 114 is of a length slightly more than onehalf the length of the circumferential travel of the outer surface ofcollar 120 and, for the first half of each cycle of rotation of collar120 during the opening or closing of the door, chain 114 is unwound fromcollar 120 and during the remaining half of each cycle is wound ontocollar 120, for purposes to be described.

In operation, as described in my aforementioned US. Patent 3,248,630 thelight beam from the headlights 130 of a vehicle 132, when directed tolight sensitive cell 134, energizes motor 68 to open, or close, thedoor, depending upon whether the door is to be opened or closed and thepreset condition of reversing switch 136, all as described in myaforementioned patent. For the first half of the operating of theopening or closing cycle, chain 114 is unwound from collar 120 and, forthe remainder of the cycle, is wound onto collar 120. During normaloperation, collar 120 rotates with shaft 66 and there is no slippagebetween collar 120 and shaft 66. Because chain 114 is slightly longerthan half of the circumferential travel of collar 120, chain 114 isunwound from and rewound on collar 120 as the collar rotates with theshaft during normal operation. Thus, during such normal operation, thereis no movement of contact 92 and, insofar as switch 80 is concerned,electrical power to motor 68 is maintained.

If, during the operation of motor 68 to open, or close, door 2, door 2should encounter an obstruction or be held, the increased load on cable46 overcomes the frictional door-driving urge applied by spring 70 uponcable 46, allowing slippage by cable 46, thereby preventing overload anddamage to motor 68. Thus, while door 2 is in engagement and held by theobstruction motor 68 and shaft 66 continue to rotate. Such continuedrotation also continues the rotation of collar 120 to wrap chain 114around rotating collar 120. After the full length of chain 114 is woundonto collar 120, the continued rotation of collar 120 with motor 68 andshaft 66 causes chain 114 and spring 110 to move rod 100, moveable mount94 and moveable contact 92 upward in housing 82 of switch 80, separatingcontacts 84, 92 and opening the circuit to motor 68. When contacts 84,92 are opened, electrical power to motor 68 is cut off and the motor isstopped. Thus, when door encounters an obstruction or is held, operationof motor 68 continues only until contacts 84, 92 are opened. Theobstruction, or whatever else might be holding door 2, can then beremoved. Once the obstruction is removed and the door is free tooperate, collar 120 can be rotated, manually, on shaft 60, to free chain114, close contacts 84, 92 and, by continued manual rotation of collar120, the interrupted cycle of motor 68, shaft 66, whether opening orclosing door 2, can be completed and, after completion, collar 120 canbe manually rotated on shaft 66 a few degrees further to reset safetyswitch for subsequent normal operation of the door. To facilitate manualrotation of collar 120, or to loosen chain 114, chain 114 may bedetached from collar 120, by hand, and re-attached after collar 120 isreset. For this purpose, a ball-chain is preferred and the ball-chain114 may be attached to collar 120 by a suitable ballchain attachment,such as a Type A coupling as manufactured by Ball Chain ManufacturingCompany, Inc., Mount Vernon, NY.

If, while door 2 is being held by an obstruction, and motor 68 and shaft66 are rotating and turning collar 120, switch 80 should become jammedor frozen so that contacts 84, 92 cannot be opened by chain 114 andspring 110, collar 120 slips on shaft 66 thereby avoiding damage to themotor, shaft, switch and housing. It is preferred, however, thatcontacts 84, 92 open and stop motor 68.

In carrying out the instant invention, rod of switch 80 could, ofcourse, be connected to collar 120 by various mechanical connections.Because of the mechanical linkages of the motor reversing mechanism, notshown on the instant drawings, it is preferred, however, to use theillustrated arrangement of spring and chain 114. In such arrangement,spring 110, as chain 114 is wound on to and unwound from collar 120,directs the chain into the area under the motor and out of the way ofthe mechanical reversing linkage.

The terms and expressions which have been employed are used as terms ofdescription and not of limitation, and there is no intention in the useof such terms and expressions of excluding any equivalents of thefeatures shown and described or portions thereof, but it is recognizedthat various modifications are possible within the scope of theinvention described.

What is claimed is:

1. A door-operator comprising, a motor, a door, a shaft on said motor, agrip-sheave on said shaft, an endless cable connected to said door andaround said grip-sheave so that, when said motor is driven in a firstdirection, said motor drives said grip-sheave and opens said door and,when said motor is driven in the opposite direction, said motor drivessaid grip-sheave and closes said door, power means connected to saidmotor for driving said motor in said first and said opposite directions,a switch in the connection of said power means to said motor and meanson said motor shaft connected to said switch for opening said switch andstopping said motor after said motor has driven said grip-sheave througha full cycle in a first direction to open said door and through a fullcycle in the opposite direction to close said door, said grip-sheaveincluding means for slipping said endless cable on said gripsheave whensaid door is obstructed while being driven by said motor in said firstand said opposite directions so that after said motor has driven saidgrip-sheave through a full cycle in said first or opposite direction andsaid door is obstructed said means on said motor shaft connected to saidswitch will open said switch and stop said motor.

2. A door-operator as recited in claim 1 in which said means on saidshaft is a collar and said collar is connected to said switch by achain.

3. A door-operator as recited in claim 2 in which said collar isconnected to said switch by a chain and spring.

4. A door-operator as recited in claim 3 in which said chain in unwoundfrom and wound onto said collar as said motor drives said grip-sheave.

5. A door-operator as recited in claim 4 in which said chain is aboutone-half the length through which the cir cumference of said collar isdriven when said motor is driving said grip-sheave through a full cycleto open said door and through a full cycle to close said door.

6. A door-operator as recited in claim 5 in which said grip-sheaveincludes a first disc, a second disc and a compression spring, saidcompression spring urging said discs into gripping engagement with saidcable.

7. A door-operator comprising, a motor, a door, a shaft on saidrnotor,door-drive connections from said shaft to said door for opening saiddoor when said motor is driven in a first direction and for closing saiddoor when said motor is driven in the opposite direction, power meansconnected to said motor for driving said motor in said first and saidopposite directions, a switch in the connection of said power means tosaid motor and means connected to said switch for opening said switchand stopping said motor after said motor has driven said door through afull cycle in said first direction to open said door and through a fullcycle in said opposite direction to close said door, said door-driveconnections from said shaft to said door including means which, whensaid door engages an obstruction while said motor is opening or closingsaid door, permits said motor to drive said shaft While said door is soobstructed so that after said motor has driven said shaft through one ofsaid cycles and said door is obstructed said means connected to saidswitch opens said switch and stops said motor.

8. A door-operator as recited in claim 7 in which said means connectedto said switch is a collar on said shaft and said collar is connected tosaid switch by a chain.

9. A door-operator as recited in claim 8 in which said collar isconnected to said switch by a chain and spring.

10. A door-operator as recited in claim 9 in which said chain is unwoundfrom and wound on said collar as said motor drives said shaft.

11. A door-operator as recited in claim 10 in which said chain is aboutone-half the length through which the circumference of said collar isdriven when said motor is driving said shaft through a full cycle toopen said door and through a full cycle to close said door.

References Cited UNITED STATES PATENTS 3/1951 Hall 49-499 4/1966 Purdy318--266 US. Cl. X.R.

